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Arterial pseudoaneurysms are among of the most frequently encountered complications of interventional vascular procedures. Pseudoaneurysms are contained pulsatile hematomas that arise from arterial puncture sites that fail to fully seal. Historically, pseudoaneurysms required surgical vessel closure, though now ultrasound-guided thrombin injection has now become the mainstay first-line treatment. The safety and efficacy of ultrasound-guided thrombin injection for femoral pseudoaneurysms has been well established in large trials and systematic reviews. [1] However, despite the increasing popularity of upper extremity endovascular access, reports of non-groin pseudoaneurysms treatment are limited.

In this study, Valesano et al. at the Mayo Clinic retrospectively review 39 cases of thrombin injection treatment for non-groin pseudoaneurysms. Of these 29 were in the upper extremity and 20 of those were of the brachial artery. Thirty-six were iatrogenic of nature and 22 of those were from arterial access. They report a 100% success rate in achieving zero Doppler flow immediately after thrombin injection and an 84.8% success rate in sustained thrombosis at 1-3 days after treatment

Clinical Pearls

Though there are many techniques, what are the general steps in ultrasound guided thrombin injection?

The authors describe their technique as follows:

1. Obtain baseline arterial duplex US imaging and Dopper waveforms of both the pseudoaneurysms and the origin artery proximal and distal to the site.

7. Follow-up imaging with duplex and Doppler US is recommended one day after the procedure.

What are the characteristics of pseudoaneurysms at higher risk of treatment failure?

It is difficult to draw conclusions from the small number of treatment failures from this series, however it appeared that the neck size was more predictive than the total size. The average size of pseudoaneurysms that remained successfully thrombosed at follow up were larger at 2.3cm +/- 1.6, while the average size for treatment failures were 2.0cm +/- 0.7. The neck diameter for treatment failures averaged 2.6 mm +/- 0.5 and 2.1 mm +/- 0.8 for treatment successes. Because of the small sample size, these results trended towards, but did not show statistical significance. Of the treatment failures, three were successfully treated with one retreatment, and the other two were successfully treated after two retreatments.

Questions to Consider

Though the authors reported no complications, what are the potential complications of this procedure?

In the small previous reports, there have been two incidents of brachial artery thrombosis. In 2014, Garvin et al reported 14 cases of treatment with thrombin in the upper extremities. [2] In one of these cases, brachial artery thrombosis was identified by decreased Doppler amplitude distal to the pseudoaneurysm fifteen minutes after treatment. Emergent surgical revascularization was performed. Kang et al reported 5 upper extremity treatments in 2000. [3] In one case, the neck of the pseudoaneurysm persisted after initial thrombin injection, and after a small amount was injected into the residual neck, the patient began to experience symptoms of hand ischemia. Pulses returned and symptoms resided in less than ten minutes after treatment with 5000 IU of heparin.

What special considerations should be taken in patients on anticoagulation therapy?

Successful pseudoaneurysm treatment with thrombin in the setting of concurrent anticoagulation therapy has been well documented for femoral pseudoaneurysms in patients on heparin, warfarin, clopidogrel, and aspirin. [4] While the authors of this study did not report the anticoagulation status of the treated patients, in the previously mentioned study of 14 cases, 9 patients were on anticoagulants for atrial fibrillation. The efficacy in anticoagulated patients compared to ultrasound-guided compression remains one of the leading justifications for thrombin therapy. Additional Sources